Subject: Re: AODI

From: Vernon Schryver <[email-masked]>
Date: Fri, 12 Nov 1999 11:40:24 -0700 (MST)

> From: Jonathan Goodchild <[email-masked]>

> ...
> But the multilink issue seems more important.  Should AODI proceed on
> the standards track with such an incompatibility?  Surely someone else
> must have an opinion.

Since you ask, I've always thought the requirement in the AODI community
for BACP/BAP indicated that the community and draft were being driven by
marketing concerns that don't care about mere technical issues, and
therefore, technnical comments would not be appropriate nor welcome.

You absolutely never need BACP for adding or dropping a second ISDN B if
you know its phone number.  BACP is similarly useless and irrelevant if
you are adding a first B channel to an MP bundle that already contains a
modem, leased line, or wet string.  Therefore you don't need BACP to add
a B channel when the MP bundle contains a D channel.

About James Carlson's very good point about the incompatibility of the
draft with RFC 1990, it seems to me the right solution is the obvious one.
As soon as you get the first B channel up, do the normal MP dance to
shutdown down D channel.  Just before dopping the last B channel, do the
normal MP (not! BACP) dance to add the D channel.

You could even modify the normal MP dropping dance to not send any D
channel LCP shutdown packets, if you care avoiding about per-packet
charges.  The MP dropping dance necessarily works when a B channel or
modem is disconnected, so as soon as you get the first B channel LCP
Configure-Request (or later at the second Configure-Ack), rip the D channel
out of the MP bundle.  You might leave any x.25 state unchanged.  This
would be completely compliant with RFC 1990, and except for BACP stupidity,
would probably even interoperate with existin AODI implementations.

Vernon Schryver    [email-masked]